Both.
Yes
1gb online storage
You can only buy it online. But you can play the maps offline there after.
they have to get the kills first!
its will show you when you first get the game to adjust it to your own screen.
Once you are on the Black Ops multiplayer screen go to store and you will see the First Strike map pack for 15 Dollars.
Ascension is the only zombie map in First Strike
You buy a card in a store, which you enter online through your xbox.
The first strike map pack cost $15.00
you can get first strike for free on PC, PS3 and XBOX just visit:
First strike and the 3 later DLCs were already released for Black ops
First Strike